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Updated: Jun 2, 2026
Quantitative Magnetic Resonance Imaging of Skeletal Muscle Disease
Published on: December 18, 2016
Optimization of the balanced steady state free precession (bSSFP) pulse sequence for magnetic resonance imaging of
Christiane L Mallett1, Paula J Foster
1Department of Medical Biophysics, The University of Western Ontario, London, Ontario, Canada. cmall@imaging.robarts.ca
Introduction:
MRI can be used to non-invasively monitor tumour growth and response to treatment in mouse models of prostate cancer, particularly for longitudinal studies of orthotopically-implanted models. We have optimized the balanced steady-state free precession (bSSFP) pulse sequence for mouse prostate imaging.
Methods:
Phase cycling, excitations, flip angle and receiver bandwidth parameters were optimized for signal to noise ratio and contrast to noise ratio of the prostate. The optimized bSSFP sequence was compared to T1- and T2-weighted spin echo sequences.
Results:
SNR and CNR increased with flip angle. As bandwidth increased, SNR, CNR and artifacts such as chemical shift decreased. The final optimized sequence was 4 PC, 2 NEX, FA 50°, BW ±62.5 kHz and took 14-26 minutes with 200 µm isotropic resolution. The SNR efficiency of the bSSFP images was higher than for T1WSE and T2WSE. CNR was highest for T1WSE, followed closely by bSSFP, with the T2WSE having the lowest CNR. With the bSSFP images the whole body and organs of interest including renal, iliac, inguinal and popliteal lymph nodes were visible.
Conclusion:
We were able to obtain fast, high-resolution, high CNR images of the healthy mouse prostate with an optimized bSSFP sequence.
Insights
Optimized balanced steady-state free precession (bSSFP) MRI sequences provide fast, high-resolution prostate imaging in mice. This technique enhances visualization of tumors and surrounding lymph nodes for cancer research.
Area of Science:
- Biomedical Imaging
- Preclinical Cancer Research
- Magnetic Resonance Imaging
Background:
- Magnetic Resonance Imaging (MRI) enables non-invasive monitoring of tumor growth and treatment response in mouse models.
- Orthotopically-implanted mouse models are crucial for longitudinal prostate cancer studies.
- Optimization of MRI pulse sequences is essential for high-quality imaging.
Purpose of the Study:
- To optimize the balanced steady-state free precession (bSSFP) pulse sequence for enhanced mouse prostate imaging.
- To compare the optimized bSSFP sequence with conventional T1- and T2-weighted spin echo sequences.
- To improve signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) for better visualization.
Main Methods:
- Optimized parameters including phase cycling, excitations, flip angle, and receiver bandwidth for bSSFP sequence.
- Evaluated SNR and CNR performance across different parameter settings.
- Compared the optimized bSSFP sequence against T1- and T2-weighted spin echo sequences.
Main Results:
- Optimized bSSFP sequence achieved 200 µm isotropic resolution in 14-26 minutes.
- Demonstrated higher SNR efficiency compared to T1WSE and T2WSE sequences.
- Showcased high CNR, comparable to T1WSE, and enabled visualization of the entire mouse body and key lymph nodes.
Conclusions:
- An optimized bSSFP sequence provides fast, high-resolution, and high-CNR imaging of the healthy mouse prostate.
- This optimized sequence is suitable for detailed longitudinal studies in prostate cancer mouse models.
- The technique facilitates comprehensive assessment of tumor burden and treatment efficacy.
